1. Field of the Invention
The present invention relates to a multidirectional input device in which switches can be actuated according to the arbitrary tilting direction of a control lever.
2. Description of the Related Art
As disclosed in Japanese Patent Application Laid-Open No. 7-235241, a multidirectional input device has been proposed hitherto, which roughly comprises a housing having an open top face, a cover member disposed at the open end of the housing, a switch element held inside the housing, and a control lever for actuating the switch element.
The switch element is constituted by a center fixed contact, a plurality of peripheral fixed contacts, a common contact, and a movable contact plate that are provided on the inner bottom face of the housing. The movable contact plate is always in contact with the common contact, and is apart from the center fixed contact and the peripheral fixed contacts.
The control lever is held inside the housing so as to tilt, and the top thereof projects from the cover member to the outside. The control lever is provided with a flange portion that includes a plurality of fulcrum portions facing the lower surface of the cover member, and an elastic portion formed outside the fulcrum portions.
In this multidirectional input device, when the control lever is in a neutral position, the movable contact plate is separate from the center fixed contact and the peripheral fixed contacts, and a switch-off state is obtained. When the control lever is tilted in an arbitrary direction, since it tilts on a fulcrum portion disposed on the opposite side from the tilting direction, the elastic portion positioned in the tilting direction presses the peripheral edge of the movable contact plate, and the bottom end of the control lever presses the center of the movable contact plate. Since the peripheral fixed contact positioned in the tilting direction and the center fixed contact are thereby electrically connected via the movable contact plate, a switch-on state is obtained. Therefore, even if the movable contact plate is not in contact with the center fixed contact when it is brought into contact with the peripheral fixed contact by tilting the control lever in the arbitrary direction, the elastic portion is further bent so as to bring the movable contact plate into contact with the center fixed contact.
In this multidirectional input device, however, since the movable contact plate is brought into contact with the peripheral fixed contact by the elastic portion of the control lever, it is impossible to increase the contact pressure of the movable contact plate on the peripheral fixed contact, which results in defective continuity. Moreover, a center fixed contact, and a plurality of peripheral fixed contacts surrounding the center fixed contact must be provided on the inner bottom face of the housing, and a large space is needed to place these fixed contacts therein. This enlarges the housing, and hinders size reduction of the device.
In order to eliminate the above disadvantages, the present applicant has proposed a multidirectional input device disclosed in the specification and the drawings of Japanese Patent Application No. 9-178324. FIG. 17 is a sectional view of this multidirectional input device, FIG. 18 is a top view of a drive member and an upper movable contact in the multidirectional input device, and FIG. 19 is a bottom view of a cover member in the multidirectional input device.
This multidirectional input device comprises a housing 101 and a cover member 102 that define a storage space 100, a control lever 103 held inside the storage space 100 so as to tilt, and projecting from the cover member 102, a lower fixed contact 104 in the housing 101, a lower movable contact plate 105 opposed to the lower fixed contact 104, upper fixed contacts 106a to 106h arranged on the cover member 103 at regular intervals in the circumferential direction (see FIG. 19), an upper movable contact plate 107 having a nearly circular outline and placed to face the upper fixed contacts 106a to 106h, and a coil spring 108 for pressing the upper movable contact plate 107 against the upper fixed contacts 106a to 106h. 
Referring to FIG. 17, the multidirectional input device further comprises a drive member 109 for supporting the upper movable contact plate 107, a connecting member 110 for connecting the housing 101 and the cover member 102, and a common contact 111.
When the control lever 103 is tilted, as shown in FIG. 17, the lower movable contact plate 105 makes contact with the lower fixed contact 104, and the upper movable contact plate 107 inclines on one or two of the upper fixed contacts 106 to separate from the other upper fixed contacts 106. Oblique lines in FIG. 17 show the state of continuity among the members, the upper fixed contacts 106xe2x80x94the upper movable contact plate 107xe2x80x94the coil spring 108xe2x80x94the common contact 111xe2x80x94the lower movable contact plate 105xe2x80x94the lower fixed contact 104.
The above-described configuration ensures reliable contact and separation between the lower movable contact plate 105 and the lower fixed contact 104, and reliable contact and separation between the upper movable contact plate 107 and the upper fixed contacts 106a to 106h, thereby avoiding defective continuity. Furthermore, since the lower fixed contact 104 and the upper fixed contacts 106a to 106h are mounted on separate members, it is possible to reduce the size of the multidirectional input device.
In this multidirectional input device, the eight upper fixed contacts 106a to 106h are arranged on the outer periphery of the cover member 102, as shown in FIG. 19, to respond to tilting of the control lever 103 in various directions. In order to reduce the number of components, it may be possible to omit the fixed contacts 106b, 106d, 106f, and 106h that are disposed in the oblique directions. In this case, for example, when the control lever 103 is tilted in the oblique direction, as shown by the arrow of FIG. 19, the movable contact plate 107 simultaneously makes contact with the fixed contacts 106e and 106g on both sides of the fixed contact 106 because the fixed contact 106 does not exist. When these two switches are simultaneously turned on, it is determined that the control lever 103 has been tilted in the direction of the arrow.
Since the movable contact plate 107 in this multidirectional input device has a nearly circular outline, as shown in FIG. 18, however, when it is inclined by tilting of the control lever 103, as shown in FIG. 17, the end thereof is in one-point contact with the lower surface of the cover member 102. For this reason, the control lever 103 can simultaneously and reliably turn both the switches on only within a narrow range. A dead region, where the switches are not turned on, is produced, which lowers detection accuracy in the oblique directions.
In order to solve the above problems, it is an object of the present invention to provide a reliable multidirectional input device in which detection accuracy in oblique directions is high.
According to an aspect of the present invention, there is provided a multidirectional input device including a control lever held to tilt and not to turn; a conductive flange member to be tilted by tilting of the control lever, and not to turn, such as an upper movable contact plate;.a support member opposed to the flange member so as not to tilt and turn, such as a cover member having fixed contacts arranged in the circumferential direction; a first switch having a first fixed contact to be turned on/off in response to contact and separation between the first fixed contact and the flange member according to tilting of the control lever in a first tilting direction, the first switch being constituted by, for example, the first fixed contact and the upper movable contact plate; and a second switch having a second fixed contact to be turned on/off in response to contact and separation between the second fixed contact and the flange member according to tilting of the control lever in a second tilting direction, wherein the control lever brings an end portion of the flange member into contact with the support member, and tilts on the end portion, and wherein the inclined flange member and the support member are brought into line contact or two-point contact when the first switch and the second switch are simultaneously turned on/off by tilting of the control lever.
As described above, in the present invention, when the first switch and the second switch are simultaneously turned on/off by tilting of the control lever, the inclined flange member and the support member make line contact or two-point contact with each other. In process of tilting, the operation shaft of the control lever is naturally corrected to a direction such that it is stabilized. As a result, it is possible to simultaneously turn the first switch and the second switch on/off, and to thereby provide a reliable multidirectional input device in which detection accuracy in oblique directions is high.
Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.